In recent years, a metallocene compound has been well known as a homogeneous catalyst for olefin polymerization. Many studies have been extensively carried out on a process for polymerizing an olefin with the use of a metallocene compound, especially on a process for stereoregularly polymerizing an olefin, since the report on an isotactic polymerization by W. Kaminsky et al (Angew. Chem. Int. Ed. Engl., 24,507 (1985)) has been published.
It has been known that in the polymerization of an α-olefin using a metallocene compound, the stereoregularity and the molecular weight of the obtained α-olefin polymer vary markedly by introducing a substituent on a cyclopentadienyl ring of the ligand of a metallocene compound, or bridging two cyclopentadienyl rings.
For example, there has been disclosed that when a metallocene compound having a ligand in which a cyclopentadienyl ring and a fluorenyl ring are bridged is used as a propylene polymerization catalyst, from the view point of the stereoregularity, syndioctactic polypropylene is obtained in the case of using dimethylmethylene (cyclopentadienyl)(fluorenyl)zirconium dichloride (J. Am. Chem. Soc., 110, 6255 (1988)); hemiisotactic polypropylene is obtained in the case of dimethylmethylene(3-methylcyclopentadienyl)(fluorenyl)zirconium dichloride in which a methyl group is introduced at the 3-position of a cyclopentadienyl ring [Japanese Unexamined Patent Application Publication No. H3-193796]; and isotactic polypropylene is obtained in the case of dimethylmethylene(3-tert butylcyclopentadienyl)(fluorenyl)zirconium dichloride in which a tert-butyl group is similarly introduced [Japanese Unexamined Patent Application Publication No. H6-122718]. In addition, there has been disclosed that polypropylene with improved isotactic stereoregularity is obtained in the case of using dimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(3,6-di-tert-butylfluorenyl)zirconium dichloride in which a tert-butyl group is introduced at the 3- and 6-positions of a fluorenyl ring, as compared with the case of using dimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride (WO01/27124).
Moreover, there has been disclosed that, from the view point of the molecular weight, syndiotactic polypropylene having a higher molecular weight is obtained in the case of using diphenylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride in which a bridging part of a cyclopentadienyl ring and a fluorenyl ring is replaced with a diphenylmethylene bridge, as compared with the case of using dimethylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride (Japanese Unexamined Patent Application Publication No. H2-274703); isotactic-hemiisotactic polypropylene having a higher molecular weight is obtained in the case of using diphenylmethylene(3-(2-adamantyl)cyclopentadienyl)(fluorenyl)zirconium dichloride in which a bridging part is replaced with a diphenylmethylene bridge, as compared with the case of using dimethylmethylene(3-(2-adamantyl)cyclopentadienyl)(fluorenyl)zirconium dichloride (Organometallics, 21, 934 (2002)); and isotactic polypropylene having a higher molecular weight is obtained in the case of using dimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride in which a methyl group is also introduced at the 5-position of a cyclopentadienyl ring, as compared with the case of using dimethylmethylene(3-tert-butylcyclopentadienyl)(fluorenyl)zirconium dichloride (PCT Japanese Translation Patent Publication No. 2001-526730), respectively.
Furthermore, there has been disclosed that, with the use of dimethylmethylene(3-tert-butyl-2-methylcyclopentadienyl)(fluorenyl)zirconium dichloride and diphenylmethylene(3,4-dimethylcyclopentadienyl)(fluorenyl)zirconium dichloride, in which substituents are introduced at two adjacent positions of a cyclopentadienyl ring, polypropylene having a lower molecular weight is obtained, as compared with that prepared with the use of dimethylmethylene(3-tert-butyl-5-methylcyclopentadienyl)(fluorenyl)zirconium dichloride and diphenylmethylene(3-methylcyclopentadienyl)(fluorenyl)zirconium dichloride, respectively (PCT Japanese Translation Patent Publication No. 2001-526730, and Japanese Unexamined Patent Application Publication No. H10-226694).
As described above, there have been many examples of reports on the metallocene compound having a ligand in which a cyclopentadienyl ring and a fluorenyl ring are bridged. On the other hand, as for the kinds of the substituent at the 3- and 6-positions of a fluorene ring, the reported examples have been extremely limited. Specifically, a metallocene compound in which a tert-butyl group is substituted at the 3- and 6-positions of a fluorene ring, and a metallocene compound in which the 2- and 3-positions, and the 6- and 7-positions of a fluorene ring form a saturated 6-membered ring have been known (WO01/27124), but there has been no reported examples of the synthesis and polymerization of a metallocene compound having a fluorene ring in which an unsaturated bond is substituted at the 3- and 6-positions. In addition, there has been no reported examples of the synthesis of a fluorene derivative in which a carbon-carbon unsaturated bond is substituted at the 3- and 6-positions. Thus, the performances of such metallocene compound have not been yet known.
Generally, there is a need for improvement of a polymerization catalyst with the use of these metallocene compounds from the view point of the polymerization activity, the stereoregularity, the molecular weight, or the like.
On the other hand, in recent years, since a fluorene compound has been used as an organic electroluminescence element, production of fluorene in which an unsaturated bond is substituted at the 3 and 6-positions, is also useful in these field.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. H3-193796
[Patent Document 2] Japanese Unexamined Patent Application Publication No. H6-122718
[Patent Document 3] WO 01/27124
[Patent Document 4] Japanese Unexamined Patent Application Publication No. H2-274703
[Patent Document 5] PCT Japanese Translation Patent Publication No. 2001-526730
[Patent Document 6] Japanese Unexamined Patent Application Publication No. H10-226694
[Non-Patent Document 1] Angew. Chem. Int. Ed. Engl., 24,507 (1985)
[Non-Patent Document 2] J. Am. Chem. Soc., 110, 6255 (1988)
[Non-Patent Document 3] Organometallics, 21, 934 (2002)